You will need to reconvert them to .mobi (even if they are already .mobi) to get the metadata updates that are required for "Furthest Page Read" syncing to work. "reconvert" = select them in Calibre --> Convert --> Bulk Convert --> Output format MOBI

Ok. So I select all and just do a reconvert.

1. Does it just overwrite the current file or does it make another mobi file?

2. Is it ok to do a lot at once. Or should I convert in steps, so many files at a time. I have approx. 135 books in Calibre right now.

This did not work for me. I updated to the latest version of Calibre this morning. I reconverted my library after the update and sent a new copy of each book to both my Kindle 3 WiFi and my Android phone. I opened a couple books in each and established where I was in each book by bookmarking and going to that specific location. Then I attempted to sync and nothing happened. On both devices I received a message that I was already synced to the furthest location read. But they did not sync. Both devices are on different locations. What did I do wrong?

Something to try: delete the books from both devices before uploading them. How are you getting them on your Android phone? Are you uploading the .opf file as well as the .mobi file?

Does the Fetch Annotations for Last Page Read only work for Mobi files? I have searched my library for those that contain Last Page Read in the Description comments and found they are MOBI files for which my Kindle had the MOBI file. But if I am reading an AZW file on the Kindle, there is no Last Page Read notation in my Calibre library for that book, even though I have Fetched Annotations. Could somebody explain when Fetch Annotations works and when it doesn't?

Someone suggested using book uuid as the ASIN field and set cdetype to EBOK to allow Amazon furthest read tracking to work with Calibre Mobi files. Where in the interface do you have the chance to set those?

Does the Fetch Annotations for Last Page Read only work for Mobi files? I have searched my library for those that contain Last Page Read in the Description comments and found they are MOBI files for which my Kindle had the MOBI file. But if I am reading an AZW file on the Kindle, there is no Last Page Read notation in my Calibre library for that book, even though I have Fetched Annotations. Could somebody explain when Fetch Annotations works and when it doesn't?

Someone suggested using book uuid as the ASIN field and set cdetype to EBOK to allow Amazon furthest read tracking to work with Calibre Mobi files. Where in the interface do you have the chance to set those?

I just re-converted my book using Calibre and changed the tag as above.

Then I deleted the problem book from my kindle and from my amazon manage my kindle" page, and resent the newly formatted book to my kindle via email.

I also had deleted it from my iphone app and actually removed the app from my iphone just to make sure. I reinstalled the app and the newly formatted book appeared in my cloud section. I opened it and it correctly opened on the last page read from my kindle.

Now my kindle and my iphone app send last page data back and forth perfectly.

Note that in my case only a few books were giving me trouble. So in my case it seemed the files were at fault.